JP2011156845A - Liquid jetting head and method for manufacturing liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jetting head capable of reliably preventing malfunction caused by static electricity, and to provide a method for manufacturing the liquid jetting head. <P>SOLUTION: An electrically conductive film 46 is formed under a continuous condition on at least a first face, and a second face of a nozzle plate 22 and the inner peripheral face of a nozzle 27. On the first face, a liquid repellent layer 49 is formed on parts except regions electrically communicated with electrically conductive members (a unit fixed plate 17 and a head cover 18), and the electrically conductive members are electrically communicated to the electrically communicating regions 50 where the liquid repellent layer is not formed on the first face, and are electrically grounded to the earth. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head used in a liquid ejecting apparatus such as an ink jet printer, and a method for manufacturing the same, and in particular, a nozzle forming member on which a nozzle for ejecting liquid is formed and a peripheral edge of the nozzle forming member The present invention relates to a liquid ejecting head provided with a conductive member attached to the part, and a method for manufacturing the liquid ejecting head.

  There are various types of liquid ejecting heads. For example, an ink jet recording head (hereinafter referred to as a recording head) in an ink jet recording apparatus (hereinafter simply referred to as a printer) reaches a nozzle from a common liquid chamber through a pressure chamber. What has a flow path unit in which a series of liquid flow paths are formed, an actuator unit having a pressure generating means capable of changing the volume of the pressure chamber, and a head case to which the flow path unit and the actuator unit are fixed. is there.

  The recording head is provided with a metal head cover that covers the side surface of the flow path unit and the peripheral edge of the nozzle surface of a nozzle plate (a kind of nozzle forming member) provided in the flow path unit. The head cover is connected to a ground line, and is electrically connected to the nozzle plate, thereby causing damage or error to the driving IC or the like due to static electricity generated from the recording paper or the like being transmitted through the nozzle plate. It is designed to prevent malfunctions such as operation.

  Here, from the viewpoint of preventing jetting failure such as flight bending due to ink adhering to the periphery of the nozzle and improving the wiping property when wiping the ink adhering to the nozzle surface with a wiping member, the ink on the nozzle plate is used. A liquid repellent film is formed on the surface on the jetting side, thereby improving the liquid repellency (ink repellency) of the nozzle plate surface. Since this liquid repellent film may be insulative, when the nozzle plate is made of a material such as a conductive metal, the liquid repellent film is removed from the portion where the head cover is attached, and the cover serves as a nozzle. It is comprised so that it may contact with the raw material itself of a plate and it may conduct (for example, refer to patent documents 1). In addition, when the nozzle plate is made of a material that is difficult to conduct electricity (non-conductive member), for example, a silicon single crystal substrate, a conductive film is formed on the surface of the nozzle plate on which ink is ejected. There is also a configuration in which a water repellent film is provided thereon (see, for example, Patent Document 2). Silicon is a semiconductor, but is treated as a non-conductive member in this specification.

JP 2006-256231 A JP 2000-203033 A

  However, even in the configuration in which the nozzle plate is grounded through the head cover, a part of static electricity flows to the nozzle side through the adhesive or the liquid repellent film, and this flows the ink in the liquid flow path in the head, thereby driving ICs, diaphragms, etc. As a result, there is a problem that problems such as damage to the drive IC and cracks in the diaphragm occur.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head capable of preventing or suppressing problems due to static electricity and a method of manufacturing the liquid ejecting head. is there.

The present invention has been proposed in order to achieve the above object, wherein a nozzle for ejecting liquid is formed, and a second surface opposite to the first surface on which liquid is ejected is a liquid flow. A non-conductive nozzle forming member that partitions a portion of the path;
A conductive member having electrical conductivity and contacting the first surface of the nozzle forming member;
With
The conductive film is formed in a continuous state over at least the first surface, the second surface, and the inner peripheral surface of the nozzle of the nozzle forming member,
A liquid repellent layer is formed on a portion of the first surface of the nozzle forming member other than a region electrically connected to the conductive member;
The conductive member is electrically connected to a region where the liquid repellent layer is not formed on the first surface of the nozzle forming member, and is electrically grounded.
The state in which the conductive member is in contact with the nozzle forming member includes not only a state in which the conductive member is in direct contact but also a state in which the conductive member is in indirect contact with an adhesive or the like.

  According to this configuration, the conductive film is formed in a state of being continuous over at least the first surface, the second surface, and the inner peripheral surface of the nozzle, and the first surface of the nozzle forming member A liquid repellent layer is formed in a portion other than the region that is electrically connected to the conductive member, and the conductive member is electrically connected to a region where the liquid repellent layer is not formed on the first surface of the nozzle forming member, and is electrically Therefore, even if static electricity flows to the liquid in the liquid flow path through the nozzle, the static electricity can flow to the conductive member side through the conductive film on the second surface that contacts the liquid in the nozzle forming member. This makes it possible to more reliably prevent problems such as damage to the drive IC due to static electricity.

  Further, the present invention is suitable for a configuration in which the nozzle forming member is made of a silicon single crystal substrate.

  In the above structure, a structure in which the conductive film is made of tantalum oxide can be employed.

  In the above configuration, it is desirable to employ a configuration in which the conductive member and the nozzle forming member are joined with a conductive adhesive.

  According to this configuration, since the conductive member and the nozzle forming member are joined by the conductive adhesive, rattling between the conductive member and the nozzle forming member can be prevented and conduction can be further ensured.

Furthermore, the present invention provides a non-conductive nozzle in which a nozzle for ejecting liquid is formed, and a second surface opposite to the first surface on which liquid is ejected defines a part of the liquid flow path. A liquid ejecting head manufacturing method comprising: a forming member; and a conductive member having conductivity and contacting the first surface of the nozzle forming member,
Forming a conductive film in a continuous state over at least the first surface, the second surface, and the inner peripheral surface of the nozzle of the nozzle forming member;
Forming a liquid repellent layer in a portion other than a region electrically connected to the conductive member on the first surface;
Attaching the conductive member in a state in which the conductive member is brought into contact with the region where the liquid repellent layer is not formed on the first surface of the nozzle forming member and is electrically connected to the nozzle forming member;
Electrically grounding the conductive member;
It is characterized by including.

FIG. 3 is a perspective view illustrating a configuration of a printer. FIG. 3 is an exploded perspective view of the recording head as viewed obliquely from above. It is a disassembled perspective view of a head unit. It is sectional drawing of a head unit. It is a top view explaining the state where the unit fixing plate and the cover member were attached to the head unit. It is sectional drawing explaining the manufacturing process of a nozzle plate.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following description, an ink jet recording head (hereinafter simply referred to as a recording head) mounted on an ink jet printer (a kind of the liquid ejecting apparatus of the present invention) is taken as an example of the liquid ejecting head of the present invention. .

  First, a schematic configuration of the printer will be described with reference to FIG. The printer 1 is an apparatus that records an image or the like by ejecting liquid ink onto the surface of a recording medium 2 such as recording paper. The printer 1 includes a recording head 3 that ejects ink, a carriage 4 to which the recording head 3 is attached, a carriage moving mechanism 5 that moves the carriage 4 in the main scanning direction, and a platen roller 6 that transfers the recording medium 2 in the sub-scanning direction. Etc. Here, the ink is a kind of liquid of the present invention, and is stored in the ink cartridge 7. The ink cartridge 7 is detachably attached to the recording head 3. It is also possible to employ a configuration in which the ink cartridge 7 is disposed on the main body side of the printer 1 and is supplied from the ink cartridge 7 to the recording head 3 through an ink supply tube.

  The carriage moving mechanism 5 includes a timing belt 8. The timing belt 8 is driven by a pulse motor 9 such as a DC motor. Accordingly, when the pulse motor 9 is operated, the carriage 4 is guided by the guide rod 10 installed on the printer 1 and reciprocates in the main scanning direction (width direction of the recording medium 2).

FIG. 2 is an exploded perspective view showing the configuration of the recording head 3. The recording head 3 in the present embodiment is roughly configured by a case 15, a plurality of head units 16, a unit fixing plate 17, and a head cover 18. The unit fixing plate 17 and the head cover 18 in the present embodiment constitute a conductive member in the present invention.
The case 15 is a box-shaped member that accommodates the head unit 16 and a focusing flow path (not shown) therein, and a needle holder 19 is formed on the upper surface side. The needle holder 19 is a plate-like member for attaching the ink introduction needle 20. In this embodiment, eight ink introduction needles 20 are arranged side by side in correspondence with the ink color of the ink cartridge 7. It is arranged. The ink introduction needle 20 is a hollow needle-like member that is inserted into the ink cartridge 7, and ink stored in the ink cartridge 7 is introduced into the case 15 from an introduction hole (not shown) provided at the tip. It is introduced to the head unit 16 side through the converging flow path.

  Further, on the bottom surface side of the case 15, a metal unit fixing plate 17 having four openings 17 ′ corresponding to the head units 16 in a state where the four head units 16 are positioned side by side in the main scanning direction. And is fixed by a metal head cover 18 having four openings 18 'corresponding to the head units 16, respectively.

FIG. 3 is an exploded perspective view showing the configuration of the head unit 16 (liquid ejecting head narrower than the recording head 3), and FIG. 4 is a cross-sectional view of the head unit 16. For convenience, the stacking direction of each member will be described as the vertical direction.
The head unit 16 in the present embodiment is generally configured by a nozzle plate 22, a flow path substrate 23, a common liquid chamber substrate 24, and a compliance substrate 25 (protective substrate), and is stacked on the unit case 26 in a state where these members are stacked. It is attached.

  The nozzle plate 22 (a kind of nozzle forming member in the present invention) is a member made of a silicon single crystal substrate in which a plurality of nozzles 27 are formed in rows at a pitch corresponding to the dot formation density. In the present embodiment, a nozzle row is configured by arranging 180 nozzles 27 at a pitch of 180 dpi. In addition, each nozzle 27 is formed by dry etching and is composed of two continuous cylindrical hollow portions having different inner diameters. That is, a cylinder with a small inner diameter formed on the ink ejecting side in the plate thickness direction of the nozzle plate 22 and a cylinder with a large inner diameter formed on the side opposite to the ink ejecting side (ink flow path side) A nozzle 27 is configured. The shape of the nozzle 27 is not limited to the illustrated example. For example, the nozzle 27 includes a cylindrical portion (straight portion) having a constant inner diameter and a tapered portion in which the inner diameter gradually increases from the ejection side toward the ink flow path side. May be configured. As will be described later, a conductive film 46 for imparting conductivity and a liquid repellent layer 49 for imparting liquid repellency are formed on the nozzle plate 22. Details of this point will be described later.

  The flow path substrate 23 is made of a silicon single crystal substrate, like the nozzle plate 22. As shown in FIG. 3, an extremely thin elastic film 30 made of silicon dioxide is formed on the upper surface (the surface on the common liquid chamber substrate 24 side) by thermal oxidation. As shown in FIG. 4, a plurality of pressure chambers 31 partitioned by a plurality of partition walls are formed on the flow path substrate 23 corresponding to each nozzle 27. On the outside of the row of pressure chambers 31 in the flow path substrate 23, a communication empty portion 33 is formed that partitions a part of the common liquid chamber 32 as a chamber into which ink common to the pressure chambers 31 is introduced. . The communication empty portion 33 communicates with each pressure chamber 31 via the ink supply path 34.

  On the elastic film 30 on the upper surface of the flow path substrate 23 (surface opposite to the nozzle plate 22 side), a metal lower electrode film, a piezoelectric layer made of lead zirconate titanate (PZT), and the like, A piezoelectric element 35 formed by sequentially laminating an upper electrode film made of metal is formed for each pressure chamber 31. The piezoelectric element 35 is a so-called flexural mode piezoelectric vibrator and is formed so as to cover the upper portion of the pressure chamber 31.

  On the flow path substrate 23 on which the piezoelectric element 35 is formed, the common liquid chamber substrate 24 having the through void portion 36 penetrating in the thickness direction is disposed. The common liquid chamber substrate 24 is manufactured using a silicon single crystal substrate in the same manner as the flow path substrate 23 and the nozzle plate 22. Further, the through space 36 in the common liquid chamber substrate 24 communicates with the communication space 33 of the flow path substrate 23 so as to partition a part of the common liquid chamber 32.

  A drive IC 38 for driving each piezoelectric element 35 is provided on the upper surface of the common liquid chamber substrate 24 (surface opposite to the flow path substrate 23). Each terminal of the drive IC 38 is connected to a lead wiring drawn from the individual electrode of each piezoelectric element 35 via a bonding wire or the like (not shown). Each terminal of the drive IC 38 is electrically connected to a control unit (not shown) of the printer 1 via an external wiring 39 (see FIG. 3) such as a flexible printed cable (FPC). Various signals such as a print signal from the control unit side are supplied via the control unit.

  A compliance substrate 25 is disposed on the upper surface side of the common liquid chamber substrate 24. An ink introduction port 40 for supplying ink from the ink introduction needle 20 side to the common liquid chamber 32 penetrates in the thickness direction in a region of the compliance substrate 25 facing the through space portion 36 of the common liquid chamber substrate 24. Is formed. In addition, the region other than the ink introduction port 40 in the region facing the through space portion 36 of the compliance substrate 25 is a flexible portion 41 that is formed extremely thin. The common liquid chamber 32 is partitioned and formed by sealing the upper opening. The flexible portion 41 functions as a compliance portion that absorbs pressure fluctuations of the ink in the common liquid chamber 32.

The unit case 26 communicates with the ink introduction port 40 and is formed with an ink introduction path 42 for supplying the ink introduced from the ink introduction needle 20 side to the common liquid chamber 32 side. This is a member in which a concave portion 43 that allows expansion of the flexible portion 41 is formed in a region to be formed. A hollow portion 44 penetrating in the thickness direction is provided in the central portion of the unit case 26, specifically, in a region facing the drive IC 38 provided on the common liquid chamber substrate 24, and the external wiring 39 Is inserted through the empty portion 44 and connected to the drive IC 38.
The nozzle plate 22, the flow path substrate 23, the common liquid chamber substrate 24, the compliance substrate 25, and the unit case 26 are heated in a state where an adhesive, a heat-welded film, or the like is disposed and laminated. Are joined together.

The recording head 3 including the head unit 16 configured as described above is attached to the carriage 4 so that the nozzle row direction coincides with the sub-scanning direction with each nozzle plate 22 facing the platen 5.
Each head unit 16 takes in ink from the ink cartridge 7 through the ink introduction path 42 from the ink introduction port 40 to the common liquid chamber 32 side, and ink channels (liquid flow paths) extending from the common liquid chamber 32 to the nozzles 27. 1 type) is filled with ink. Then, a drive signal from the drive IC 38 is supplied to the piezoelectric element 35 to cause the piezoelectric element 35 to bend and deform, thereby causing a pressure fluctuation in the corresponding pressure chamber 31 and using the pressure fluctuation of the ink. Ink is ejected from the nozzles 27.

Next, the details of the nozzle plate 22, particularly the manufacturing process thereof, will be described.
FIG. 6 is a schematic diagram for explaining the manufacturing process of the nozzle plate 22.
As the material of the nozzle plate 22 in the present embodiment, the above-described silicon single crystal substrate 22 ′ is used, and a plurality of nozzle plates 22 are produced from one substrate 22 ′. As shown in FIG. 6A, first, nozzles 27 are formed on the substrate 22 'by dry etching (nozzle forming step). Next, as shown in FIG. 6B, the surface on which ink is ejected (the lower surface in the drawing; hereinafter referred to as the first surface), the surface opposite to this surface (the upper surface in the drawing) The conductive film 46 is formed on the surface (hereinafter referred to as the second surface) and the inner peripheral surface of the nozzle 27 (conductive film forming step). The conductive film 46 is preferably conductive and ink-resistant. In the present embodiment, the conductive film 46 is composed of a tantalum oxide film. The conductive film 46 is formed by a chemical vapor deposition (CVD) method, and the film thickness is about 100 nm. As described above, the conductive film 46 has at least the first surface (particularly, a region in contact with the conductive member (hereinafter referred to as a conduction region 50)) and the second surface (particularly, ink in the ink flow path). Region) and the inner peripheral surface of the nozzle 27, and the conductive films 46 in these regions may be continuous with each other. Of course, other than these regions, for example, a configuration in which the conductive film 46 is formed on the side surface of the nozzle plate 22 may be employed.

  If the conductive film 46 is formed on the substrate 22 ', then the liquid repellent layer 49 is formed on the conductive film 46 on the first surface (liquid repellent layer forming step). Specifically, a base film (PPSi (Plasma Polymerization Silicone) film) 47 is formed by plasma polymerizing a silicon material first (FIG. 6C), and a liquid repellency is provided on the base film 47. A molecular film of the metal alkoxide is formed, and then a liquid repellent film (SCA (silane coupling agent) film) 48 is formed through a drying process, an annealing process, and the like (FIG. 6D). Any metal alkoxide molecular film may be used as long as it has liquid repellency, but a metal alkoxide monomolecular film having a long-chain polymer group containing fluorine (long-chain RF group) or a metal having a liquid-repellent group. A monomolecular film of an acid salt is desirable. As the metal alkoxide, for example, silicon, titanium, aluminum, zirconium and the like are generally used. Examples of the long chain RF group include a perfluoroalkyl chain and a perfluoropolyether chain. Examples of the alkoxysilane having a long chain RF group include a silane coupling agent having a long chain RF group.

  Here, since the liquid repellent layer 49 is electrically insulative compared to the conductive film 46, a region where the conductive member is attached and conducted on the first surface, that is, other than the conductive region 50. It is formed only in the region. With respect to the conductive region 50, the liquid repellent layer 49 may be removed only after the liquid repellent layer 49 is formed on the entire first surface, or only the part corresponding when the liquid repellent layer 49 is formed. By masking, the liquid repellent layer 49 may not be formed from the beginning in the portion.

  If the liquid repellent layer 49 is formed, the substrate 22 ′ is divided to obtain a plurality of nozzle plates 22. Through such steps, the nozzle plate 22 is manufactured. The flow path substrate 23 is joined to the second plate side of the nozzle plate 22. As a result, the second surface defines a part of the ink flow path such as the pressure chamber 31 and the common liquid chamber 32, so that the conductive film 46 is exposed to the ink flow path and can contact the ink in the ink flow path. It becomes a state. In the present embodiment, the four head units 16 are attached to the unit fixing plate 17 in a state of being positioned side by side in the main scanning direction (conductive member attaching step). The unit fixing plate 17 is joined to the conduction region 50 of the nozzle plate 22 of each head unit 16 by a conductive adhesive 51. As the conductive adhesive 51, for example, a paste-like adhesive containing a conductive material such as a metal powder such as silver, nickel, or copper, or a conductive polymer plated with gold can be used. Moreover, it is not restricted to a paste-form adhesive, The film-form adhesive which has electroconductivity can also be used. In addition, if the unit fixing plate 17 and the nozzle plate 22 are joined in an electrically conductive state, the joining method is not limited to the exemplified joining method.

  When the unit fixing plate 17 and the nozzle plate 22 of each head unit 16 are joined, the head cover 18 is attached so as to overlap the unit fixing plate 17 (conductive member attaching step). A configuration in which the head cover 18 and the unit fixing plate 17 are also joined by a conductive adhesive can be employed. As described above, in this embodiment, since the conductive member and the nozzle plate 22 are joined by the conductive adhesive, it is possible to prevent rattling between the conductive member and the nozzle plate 22 and to further ensure conduction. it can.

  When the unit fixing plate 17 and the head cover 18 are attached, as shown in FIG. 5, the nozzle openings 27 of the nozzle plate 22 of each head unit 16 are opened from the openings 17 ′ and 18 ′ of the unit fixing plate 17 and the head cover 18. Come on. The head cover 18 is electrically connected to a ground wire (not shown) (grounding step). Therefore, the conductive film 46 of the nozzle plate 22 is grounded through the unit fixing plate 17 and the head cover 18 which are conductive members.

  As described above, the conductive film 46 is continuously formed on at least the first surface, the second surface, and the inner peripheral surface of the nozzle 27 of the nozzle plate 22, and a conductive member (unit) is formed on the first surface. A liquid repellent layer 49 is formed in a portion other than the region that is electrically connected to the fixing plate 17 and the head cover 18), and the conductive member is electrically connected to a region where the liquid repellent layer 49 is not formed on the first surface; Since the conductive film 46 is formed on the second surface of the nozzle plate 22 in contact with the ink even if static electricity flows to the ink in the ink flow path through the nozzle 27, the conductive film 46 is formed. Static electricity can be released to the conductive member side through the conductive film 46 (see arrows in FIG. 6E). As a result, it is possible to more reliably prevent problems such as damage to the drive IC 38 due to static electricity.

  Here, with respect to the nozzle plate 22, in the present embodiment, an example in which the silicon plate is manufactured from a silicon single crystal substrate is shown. However, the present invention is not limited to this, and other non-conductive materials that require the formation of the conductive film 46. The present invention is also suitable when the nozzle plate 22 is manufactured from a member such as glass or quartz.

  In FIG. 6, a gap is provided between the liquid repellent layer 49 and the fixing plate 17 and the head cover 18 over the surface direction of the nozzle surface, but with respect to the stacking direction of the nozzle plate 22 and the fixing plate 17, A part of the adhesive layer 49 and a part of the fixing plate 17 and the head cover 18 may be bonded by the conductive adhesive 51 so as to overlap each other.

  In the above description, the ink jet recording head 3 which is a kind of liquid ejecting head has been described as an example, but the present invention can also be applied to other liquid ejecting heads. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of

  DESCRIPTION OF SYMBOLS 1 ... Printer, 3 ... Recording head, 16 ... Head unit, 17 ... Unit fixing plate, 18 ... Head cover, 22 ... Nozzle plate, 23 ... Flow path substrate, 27 ... Nozzle, 31 ... Pressure chamber, 32 ... Common liquid chamber, 35 ... piezoelectric element, 38 ... driving IC, 46 ... conductive film, 47 ... undercoat film, 48 ... liquid repellent film, 49 ... liquid repellent layer, 50 ... conductive region, 51 ... conductive adhesive

Claims (5)

A non-conductive nozzle forming member in which a nozzle for ejecting liquid is formed, and a second surface opposite to the first surface on which liquid is ejected defines a part of the liquid flow path;
A conductive member having electrical conductivity and contacting the first surface of the nozzle forming member;
With
The conductive film is formed in a continuous state over at least the first surface, the second surface, and the inner peripheral surface of the nozzle of the nozzle forming member,
A liquid repellent film is formed on a portion of the first surface of the nozzle forming member other than a region electrically connected to the conductive member;
The liquid ejecting head according to claim 1, wherein the conductive member is electrically connected to an area where the liquid repellent film is not formed on the first surface of the nozzle forming member and is electrically grounded.   The liquid ejecting head according to claim 1, wherein the nozzle forming member is made of a silicon single crystal substrate.   The liquid ejecting head according to claim 1, wherein the conductive film is made of tantalum oxide.   4. The liquid ejecting head according to claim 1, wherein the conductive member and the nozzle forming member are bonded with a conductive adhesive. 5. A non-conductive nozzle forming member in which a nozzle for ejecting liquid is formed, and a second surface opposite to the first surface on which liquid is ejected defines a part of the liquid flow path; And a conductive member that contacts the first surface of the nozzle forming member,
Forming a conductive film in a continuous state over at least the first surface, the second surface, and the inner peripheral surface of the nozzle of the nozzle forming member;
Forming a liquid repellent film on a portion other than the region electrically connected to the conductive member on the first surface;
Attaching the conductive member in a state in which the conductive member is brought into contact with the region where the liquid repellent film is not formed on the first surface of the nozzle forming member and is electrically connected to the nozzle forming member;
Electrically grounding the conductive member;
A method of manufacturing a liquid ejecting head, comprising:

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